1. Field of the Invention
This invention relates to activation and deactivation of electronic article surveillance markers, tags, and/or labels used for triggering electronic article surveillance systems. More particularly, the invention relates to selective activation or deactivation of electronic article surveillance markers moving along a conveyor, such as in a manufacturing or distribution environment.
2. Description of Related Art
Inventory shrinkage, or loss of inventory due to theft and pilferage, is a substantial problem in the retail industry. Costs associated with inventory shrinkage can be significant for the retailer, and are often passed along to the consumer resulting in higher prices to the general public. In addition, some businesses may experience a loss of capital equipment due to employee theft. Several technical solutions have been implemented in the retail and other industries to reduce inventory shrinkage and loss of capital equipment. One solution involves attaching a tag, marker, or label (referred to herein as marker) to the retail or other article which, when brought into the vicinity of prepositioned sensors, triggers an electronic article surveillance (EAS) system which alerts store or security personnel.
Electronic article surveillance (EAS) systems and associated markers are known in the art, and encompass several different yet related technologies used to sense the markers that trigger the systems. Active markers typically react to an electromagnetic interrogation signal in a manner that is clearly recognized by the system's receiver(s). The EAS system's transmit and receive sensors are placed in preselected locations, generally at the store's exits to prevent the unauthorized removal of articles.
The EAS markers can be attached to products and articles by conventional methods such as fasteners, adhesives, hang tags and the like. Once an active marker is attached to an article, when the article passes through the EAS sensors near the business or retail store's exit, the marker is immediately identified by the EAS system. When an active EAS marker is identified by the EAS system, store or security personnel can be automatically alerted, normally by sounding an audible alarm signal.
In a retail environment, if the article is being purchased, the cashier removes, or deactivates the marker. Deactivated markers are not identified by the EAS system when brought into the vicinity of the EAS sensors. Thus, when carried out of the store, purchased articles having attached deactivated markers will not trigger the EAS system.
One example of a particularly well suited marker for use in electronic article surveillance systems as described above is the magnetomechanical marker disclosed in U.S. Pat. No. 4,510,489, issued to Philip M. Anderson, III et al. (the '489 patent), the disclosure of which is incorporated herein by reference.
The marker of the '489 patent produces a specific signal characteristic when exposed to a magnetic field. The marker is adapted to resonate mechanically at a frequency within the range of the incident magnetic field. The marker includes a magnetostrictive material and ferromagnetic element that are positioned adjacent each other such that, when the ferromagnetic element is magnetized, the magnetostrictive material is biased to resonate at a specific frequency. When the ferromagnetic material of the marker is magnetized, the marker is said to be armed or activated. When an armed marker is placed in the magnetic field generated by the EAS system's interrogation sensor(s) it resonates at the expected frequency and is identified by the system's receive sensor(s) as disclosed in the '489 patent.
The markers of the '489 patent are activated by magnetizing the ferromagnetic elements of the markers by exposing the markers to a magnetization field. The magnetization field can be a DC generated magnetic pulse. Deactivation is accomplished by demagnetization of the ferromagnetic elements by exposure to a degaussing field or exposure to a magnetic field that changes the magnetic bias such that the resonant frequency of the marker is shifted outside the range of the interrogation magnetic field and the receive sensors.
Other EAS systems use markers that include tunable electronic circuits such as those disclosed in U.S. Pat. No. 5,608,379 issued to Narlow et al., and as disclosed in U.S. Pat. No. 5,059,951 issued to Kaltner.
Typically, active markers are shipped to the retailer and attached to articles at the point-of-sale in the retail environment in conventional manner as discussed herein above. A deactivation system is available to retail cashiers so markers can be deactivated upon purchase of the attached article.
More recently, attaching markers to articles at the point-of-manufacturing or distribution has been introduced as a desirable alternative to point-of-sale attachment. In point-of-manufacturing, commonly called "source tagging", markers are attached to articles during the assembly or packaging process before being shipped to the ultimate retail business establishment. Alternately, source tagging can include activation or deactivation of markers at distribution centers.
In source tagging, the manufacturer or distributer may attach an active marker on all products assembled or packaged in an automated assembly line. However, the manufacturer, or distributer, may not want all the products to be shipped with an active marker attached. For example, the manufacturer may sell some of the products to retailers that do not have an EAS system. If the retailer sells the product without deactivating the marker, which was incorporated during manufacturing, that article could be carried to a store having an EAS system and inadvertently alert the EAS alarm.
Therefore, manufacturing and/or distribution facilities desire the ability to selectively activate or deactivate the EAS markers at one location. Manufacturers and distributors also desire to activate or deactivate the markers in an automated assembly line to prevent delays and disruption in the flow of products.
In addition, the manufacturer or distributer may sell certain products that could be damaged by electromagnetic activation or deactivation fields. The manufacturer or distributer should be able to control the activation/deactivation system to prevent damage to certain products. Moreover, there exists a need for EAS marker manufacturers to activate markers in bulk, preferably while the markers are being transported along a conveyor system prior to shipment to users.
Conventionally, activation and deactivation of EAS markers has been accomplished by separate devices in separate locations. Normally, marker activation was performed by the marker manufacturer and deactivation by the retailer. Accordingly, source tagging creates the need for selective activation and deactivation in one location by the manufacturer or distributer in a dynamic environment that is adaptable to assembly line or conveyor systems. The instant invention addresses these needs as described herein.